INRA, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, F-84000 Avignon, France.
Biomacromolecules. 2013 Mar 11;14(3):709-18. doi: 10.1021/bm301796y. Epub 2013 Feb 19.
The interactions between procyanidins and pectic compounds are of importance in food chemistry. Procyanidins with low (9) and high (30) average degrees of polymerization (DP9 and DP30) were extracted from two cider apple varieties. Commercial apple and citrus pectins, as well as three pectin subfractions (homogalacturonans, partially methylated homogalacturonans with degree of methylation 30 and 70) at 30 mM galacturonic acid equivalent, were titrated with the two procyanidin fractions (at 30 mM (-)-epicatechin equivalent) by isothermal titration calorimetry and UV-vis spectrophotometry. Slightly stronger affinities were recorded between commercial apple or citrus pectins and procyanidins of DP30 (Ka = 1460 and 1225 M(-1) respectively, expressed per monomer units) compared to procyanidins of DP9 (Ka = 1240 and 1085 M(-1), respectively), but stoichiometry and absorbance maxima differed between apple and citrus pectins. It was proposed that methylated homogalacturonans interacted with procyanidins DP30 mainly through hydrophobic interactions. The stronger association was obtained with the longer procyanidin molecules interacting with highly methylated pectins.
原花青素与果胶化合物之间的相互作用在食品化学中很重要。从两种苹果品种中提取了聚合度低（9）和高（30）的原花青素（DP9 和 DP30）。用等温滴定微量热法和紫外可见分光光度法，用两种原花青素（30 mM（-）-表儿茶素当量）滴定 30 mM 半乳糖醛酸当量的商业苹果和柑橘果胶以及三种果胶亚组分（同聚半乳糖醛酸、部分甲基化同聚半乳糖醛酸，甲基化度分别为 30 和 70）。与 DP9 原花青素（Ka = 1240 和 1085 M（-1），分别表示为单体单元）相比，商业苹果或柑橘果胶与 DP30 原花青素（Ka = 1460 和 1225 M（-1））之间的亲和力略强，但苹果和柑橘果胶的化学计量和吸光度最大值不同。据推测，甲基化的同聚半乳糖醛酸与 DP30 原花青素主要通过疏水相互作用相互作用。较长的原花青素分子与高度甲基化的果胶相互作用，从而获得更强的缔合作用。
